1. Field of the Invention
The present invention relates to an apparatus for Manufacturing soft capsules.
2. Description of the Related Art
It is conventionally known that soft capsules, with material such as medicines charged inside capsule films, formed from animal materials such as gelatin and from vegetable materials such as starch, are in common use mainly for medical and pharmaceutical products. Such soft capsules are generally manufactured by using rotary type manufacturing apparatuses as disclosed in Japanese Patent Laid-Open No. 11-221267.
As disclosed in the above document, a rotary type manufacturing apparatus consists of a sheet forming part that forms a gelatin sheet from a gelatin material, and a capsule forming part that forms capsules from the gelatin sheet. Two gelatin sheets formed in the sheet forming part are inserted between a pair of die rolls of the capsule forming part and are heat-sealed, while, a material is filled in between the gelatin sheets. The gelatin sheets are die-cut into a capsule shape with dies on a die roll outer peripheral surface, and thus, a soft capsule charged with the material inside the gelatin film is completed.
Explaining the sheet forming part in the conventional manufacturing apparatus in more detail, a sheet forming part 50 is constructed by a spreader box 51, a film-sheet forming drum 52, and a pickup roller 53 as shown in FIG. 9.
The spreader box 51 has the function of storing a fixed amount of a raw gelatin material 11, and adhering the gelatin material 11 on the film-sheet forming drum 52 by thinly spreading it thereon. The film-sheet forming drum 52 has cooling water circulated therein and is rotatably supported, and forms a cooled and solidified gelatin sheet 13 by blowing dried cold air to the gelatin material 11 while rotating the gelatin material 11 adhered on the drum surface. The pickup roller 53 peels off the gelatin sheet 13 adhering to the film-sheet forming drum 52 and transfers the gelatin sheet 13 wound on the roller outer periphery to a capsule forming part at the subsequent step by rotation of the roller. The sheet forming parts 50 are provided by being paired at both left and right sides of the die roll, and the two gelatin sheets 13 and 13 formed by a pair of sheet forming parts 50 and 50 are transferred to the die roll.
In the sheet forming part 50 as described above, the drive system has the structure in which a drum drive system 60 which rotates the film-sheet forming drum, and a pickup roller drive system 70 which rotates a pickup roller, are provided to be linked with each other as shown in FIG. 10. Namely, in the drum drive system 60, a timing belt 64 is looped over both a pulley of a speed reducer 62 connected to a motor 61 and a drum shaft input pulley 63 at a drum shaft center, and the film-sheet forming drum 52 is rotated by transmitting the rotation of the motor 61 to the drum shaft input pulley 63 via the timing belt 64.
Meanwhile, a drive source of the pickup roller drive system 70 is the same motor 61 as the film-sheet forming drum 52, and a drum shaft output pulley 71 sharing the shaft center with the drum shaft input pulley 63, and a pickup roller input pulley 72 are connected via an idler 73. Namely, a timing belt 75 is looped over both the drum shaft output pulley 71 and an idler shaft input pulley 74 with a small diameter, and a timing belt 77 is looped over both the pickup roller input pulley 72 and an idler shaft output pulley 76 with a large diameter. Accordingly, the rotational force which is transmitted to the drum shaft via the speed reducer 62 from the motor 61 is further transmitted to the pickup roller input pulley 72 via the idler 73, and thereby rotates the pickup roller 53.
However, in the conventional manufacturing apparatus, a linking drive method which links the drum drive system 60 and the pickup roller drive system 70 as described above is adopted in the sheet forming part 50, and therefore, the following problem occurs.
From the viewpoint of enhancing production efficiency of soft capsules, it is necessary to increase the rotational speed of the pickup roller 53 to transfer the gelatin sheet 13 supplied to the die roll at a high speed, but for this purpose, the rotational frequency of the motor 61 that is the drive source has to be increased, and with this, the rotation of the film-sheet forming drum 52 is increased in speed. However, when the film-sheet forming drum 52 is rotated at a high speed, the gelatin sheet 13 adhering to the drum surface does not dry in time, and the trouble that the gelatin sheet 13 which is hardly peeled off with the pickup roller 53 is rolled in the spreader box 51 occurs.
When such a trouble occurs, operation of the apparatus is temporarily stopped to remove the gelatin sheet 13 rolled into the spreader box 51, and the rotational frequency of the motor 61 has to be decreased to restart the operation, which causes significant reduction in productivity. An additional important factor of the above described trouble is that a variety of materials including vegetable materials such as starch are applied for soft capsule film, instead of animal materials such as gelatin contained in cows, pigs and fish, in recent years. The vegetable materials require various drying time from raw liquid material to film sheets, due to their differences in viscosity and temperature at film-sheet forming process. Another factor is speedup of the rotation of the film-sheet forming drum 52, for higher productivity.